Msimu stated the difficulty is brought about by the quality of sides that confirmed to participate in the showpiece.
The gaffer noted all outfits are top teams in their respective countries.
Msimu asked Zanzibar sports enthusiasts to pray for their team to do well.
The 2021 CECAFA Kagame Cup tournament's groups have already been organized, with Mainland Tanzania fielding Yanga and Azam FC, while Zanzibar has representatives in KMKM.
The tournament, which is expected to kick off next month in Dar es Salaam, will feature teams from six countries.
The tournament's full schedule is as follows, Group A consists of KCCA FC (Uganda), Le Messanger Ngozi FC (Burundi), and KMKM FC (Zanzibar).
Group B's outfits are Azam FC (Tanzania), Atlabara (South Sudan), and Tusker FC (Kenya).
Group C participants are Yanga (Tanzania), Nyasa Big Bullets (Malawi), and Express FC (Uganda).
Simba SC is the historic Kagame Cup champion, having won the showdown's title six times.
Kenya's soccer big guns, AFC Leopards, and Yanga have lifted the tournament's title five times apiece.
Simba SC will not be taking part in this season's CECAFA Kagame Cup tournament, to be held in Tanzania from August 1-15, because it will have rested its players for next season.
Ten teams will take part in the tournament, with Mainland Tanzania fielding two teams, Yanga and Azam FC.
The event will moreover include Altabara FC of South Sudan, Le Messager Ngozi of Burundi, APR of Rwanda, Express and KCCA FC of Uganda, Tusker FC of Kenya, and Big Bullets from Malawi which has been invited.
The KCCA FC is the defending champion of the tournament, having clinched the title in Rwanda in 2019.
The event did not take place last year because of the challenge of Coronavirus disease.
The CECAFA Club Cup is a football club tournament organized by the region's football governing body, CECAFA.
It has been known as the 'Kagame Inter-Club Cup' since 2002, when Rwanda President, Paul Kagame, began sponsoring the competition.
It is contested by clubs from East and Central Africa.